I just had a look at the slides introducing the several fascinating new developments incorporated in Mplus 7. The examples of the novel cross-classified option in Mplus all include one within-cell and two between-cell levels of analysis. However, I would like to know whether it is also possible to model the random interaction effect of the cell mean predicted by the two between-cell main effects. Raudenbush and Bryk (2002, p. 377f.) label this third between-cell level d_0jk (formula 12.2).